A variety of dosage forms, such as tablets, capsules and gelcaps are known in the pharmaceutical arts. Tablets generally refer to relatively compressed powders in various shapes. One type of elongated, capsule-shaped tablet is commonly referred to as a “caplet.” Capsules are typically manufactured using a two piece gelatin shell formed by dipping a steel rod into gelatin so that the gelatin coats the end of the rod. The gelatin is hardened into two half-shells and the rod extracted. The hardened half-shells are then filled with a powder and the two halves joined together to form the capsule.
Dosage forms having core and shell portions are well-known. Outer shell portions are provided over active cores for many reasons. The shell can, for example, provide taste-masking of bitter actives, modify the dissolution profile, delay the delivery thereof, or provide means for identifying the sources of goods.
Gelatin-coated tablets, commonly known as geltabs and gelcaps, are an improvement on gelatin capsules and typically comprise a tablet coated with a gelatin shell. Several well known examples of gelcaps are McNeil Consumer Healthcare's acetaminophen based products sold under the trade name Tylenol®. U.S. Pat. Nos. 4,820,524; 5,538,125; 5,228,916; 5,436,026; 5,679,406; 5,415,868; 5,824,338; 5,089,270; 5,213,738; 5,464,631; 5,795,588; 5,511,361; 5,609,010; 5,200,191; 5,459,983; 5,146,730; 5,942,034 describe geltabs and gelcaps and methods and apparatuses for making them. Conventional methods for forming gelcaps are generally performed in a batchwise manner using a number of stand alone machines operating independently. Such batch processes typically include the unit operations of granulating, drying, blending, compacting (e.g., in a tablet press), gelatin dipping or enrobing, drying, and printing.
Another method of producing gelatin coated dosage forms is via an enrobing process wherein two separate films made of gelatinous material are applied to opposite sides of a tablet by a pair of rotary dies, as disclosed for example, in U.S. Pat. Nos. 5,146,730 and 5,459,983. Film formulations for producing gelcaps and geltabs prepared via enrobing methods such as those disclosed in U.S. Pat. Nos. 5,146,730 and 5,459,983 typically comprise a water-based gelatin preparation having about 45% gelatin and about 9% plasticizer (glycerin and/or sorbitol) by weight. Glycerin and sorbitol can be used as single plasticizers or in combination with each other. In addition, other sugars and poly-hydroxy compounds can be used as additives and plasticizers. If a tamper-evident gelatin-coated medicine tablet is the desired end product, then the ratio of plasticizer to gelatin in the gelatin formulation should be in the range of about 1:5.
Certain dosage forms containing apertures or embossments are known. For instance, “osmotic pump” dosage forms for the administration of pharmaceutically active ingredients are known in the art. They typically comprise a semipermeable wall that surrounds a reservoir containing drug. The wall is permeable to the passage of an external fluid, impermeable to the passage of drug, and has a passageway through the semipermeable wall for delivering drug from the osmotic system. For example, U.S. Pat. No. 4,576,604 discloses an osmotic device comprising a drug compartment surrounded by a wall (coating) having a passageway therein. The wall may comprise an immediate release dose of drug, and the inner drug compartment may comprise a sustained release dose of drug.
U.S. Pat. No. 4,449,983 discloses another osmotic device comprising two separately housed drugs that are separately dispensed from the device. The device comprises two compartments, one for each drug, separated by a partition. Each compartment has an orifice for communicating with the exterior of the device.
U.S. Pat. No. 3,823,816 discloses a water-soluble package provided in the form of a hard shell capsule filled with powder, granules, or the like. The capsule is apertured, and a water-soluble barrier film covers the apertures. The film is more water soluble than the capsule so that when the package contacts water, the film rather than the capsule dissolves first, exposing the contents for dissolution and/or release by way of the apertures while the capsule is intact.
U.S. Pat. No. 5,256,440 relates to an intagliated dosage form comprising one or more circumscribed regions on its surface. The dosage form is spray coated with a latex polymer. When placed in an environment of use, the latex coating within the circumscribed region is reproducibly expelled, leaving a coated core tablet with a predefined aperture, which exposes a discrete portion of the core surface to the environment of use.